1. Field of the Invention
Embodiments of the present invention relate generally to the field of interference mitigation in the frequency spectrum commonly used by cordless telephones. More particularly, embodiments of the present invention relate to the field of identifying of interferers in a cordless telephone system spectrum.
2. Background of the Invention
Cordless telephone products today often use the license-free 2.4 GHz ISM communication spectrum. However, a number of other technologies also use this spectrum. For example, 802.11b WLAN products and other products use this spectrum. The presence of such devices cause interference with communication between the cordless telephone handset and the cordless telephone base unit. Likewise, communication between the cordless telephone base unit and the cordless telephone handset causes interference with communication occurring in other products operating in the 2.4 GHz ISM spectrum. As a result of this cross-interference, the performance of these products is often degraded.
To mitigate the effects of interference, conventional cordless telephone devices allow users to manually change channels when interference degrades communication. Other conventional cordless telephone devices automatically switch channels if a detected bit error rate exceeds a threshold. Neither approach is optimal. A better approach is to identify the interferer and then use the identification information to mitigate the effects of the interference.
However, there are problems associated with detecting the presence of such interferers in cordless telephone system communications that must be overcome for a viable solution applicable to the cordless telephone environment. One such problem is detecting the presence of the interferer in a short time. A second problem is distinguishing one interferer from another, for example, distinguishing 802.11b from other interferers in the ISM band.